Atomic structure of plant glutamine synthetase: A key enzyme for plant productivity

Hideaki Unno, Tatsuya Uchida, Hajime Sugawara, Genji Kurisu, Tatsuo Sugiyama, Tomoyuki Yamaya, Hitoshi Sakakibara, Toshiharu Hase, Masami Kusunoki

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    85 Citations (Scopus)


    Plants provide nourishment for animals and other heterotrophs as the sole primary producer in the food chain. Glutamine synthetase (GS), one of the essential enzymes for plant autotrophy catalyzes the incorporation of ammonia into glutamate to generate glutamine with concomitant hydrolysis of ATP, and plays a crucial role in the assimilation and re-assimilation of ammonia derived from a wide variety of metabolic processes during plant growth and development. Elucidation of the atomic structure of higher plant GS is important to understand its detailed reaction mechanism and to obtain further insight into plant productivity and agronomical utility. Here we report the first crystal structures of maize (Zea mays L.) GS. The structure reveals a unique decameric structure that differs significantly from the bacterial GS structure. Higher plants have several isoenzymes of GS differing in heat stability and catalytic properties for efficient responses to variation in the environment and nutrition. A key residue responsible for the heat stability was found to be Ile-161 in GS1a. The three structures in complex with substrate analogues, including phosphinothricin, a widely used herbicide, lead us to propose a mechanism for the transfer of phosphate from ATP to glutamate and to interpret the inhibitory action of phosphinothricin as a guide for the development of new potential herbicides.

    Original languageEnglish
    Pages (from-to)29287-29296
    Number of pages10
    JournalJournal of Biological Chemistry
    Issue number39
    Publication statusPublished - 2006 Sep 29

    ASJC Scopus subject areas

    • Biochemistry
    • Molecular Biology
    • Cell Biology

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    Unno, H., Uchida, T., Sugawara, H., Kurisu, G., Sugiyama, T., Yamaya, T., Sakakibara, H., Hase, T., & Kusunoki, M. (2006). Atomic structure of plant glutamine synthetase: A key enzyme for plant productivity. Journal of Biological Chemistry, 281(39), 29287-29296.